Area Forecast Discussion
Issued by NWS Upton, NY

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KOKX 081718
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1218 PM EST Thu Dec 8 2016

.SYNOPSIS...
A series of cold fronts cross the area Thursday through Friday.
High pressure builds through Saturday. Low pressure and associated
front impacts the area later Sunday and Monday. High pressure
returns Tuesday. Another front approaches Wednesday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
17Z Update - Forecast remains on track with little change to
database. Still expecting Jet`s associated thick mid/high clouds
to dissipate/move out late this afternoon as a shortwave passes.

The shortwave moves through dry, however it provides a shot of
cold air advection that increases winds out of the northwest by
late afternoon. Temperatures expect to fall slowly through the
mid to late afternoon north and west of NYC. Used a MAV/MET/ECS
blend for temperatures, which looked fairly reasonable.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
Another shortwave moves across the region Thursday night into
Friday, providing yet another shot of cold air.

In addition, there should be enough moistening of the low and mid
levels early Friday morning to warrant a slight chance of snow
showers. The best chances of any precipitation will remain north
and west of NYC, however by mid to late morning, snow showers will
be possible across the entire CWA. little to no accumulations are
expected with these snow showers.

Low temperatures Thursday night will fall into 20s and lower 30s.
A gusty northwest flow 20-30 mph will allow wind chills to reach
the teens and lower 20s around sunrise Friday morning.

High temperatures on Friday will only reach the middle and upper
30s, but will feel like 20s, as the gusty northwest flow continues.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Uncertainty due to differences in details this time frame in a
progressive flow through the weekend, then a more amplified
pattern mid week next week.

Chilly air settles in from Canada through much of this time period,
and timing of individual systems remains a challenge.

Generally expect dry weather Friday night and Saturday as initial
shortwave departs, and surface high pressure builds to the south.

Next impulse and surface boundary approaches from the west Sunday
with potential for WAA precip (likely snow) developing later Sunday
and Sunday night. On Monday, track and strength of low pressure is
unclear, but frontal boundary looks to remain south of the area.
Will maintain likely PoP for this timeframe since models agree on
precip, if not overall pattern details. P-type will be tricky
late Sunday night and Monday, with some mix or changeover likely
as warmer air advects northward.

This upper shortwave races east by Tuesday, along with low pressure
and front, although 00Z ECMWF shows lingering Norlun type trough
nearby or just east of the area early Tuesday between inland
weakening low and offshore low.

More vigorous upper trough begins to take shape, tracking across the
upper mid west and pivoting across the Great Lakes region by mid
week. Latest GFS and ECMWF runs differ on depth of this trough, and
sfc features. This leads to overall lower confidence in forecast
day 7.

Temperatures should remain at or just below normal through much of
this period. Brief warmups could occur in WAA ahead of each
shortwave/low pressure in return flow.

&&

.AVIATION /17Z THURSDAY THROUGH MONDAY/...
A cold front passes this afternoon. High pressure then builds
through Friday.

VFR through the TAF period.

W-WNW winds continue through tonight. Gusty winds will continue to
develop this afternoon, before relaxing somewhat overnight. Gusts
could become more occasional overnight, especially at outlying
terminals. Winds and gusts will increase after sunrise tomorrow
with gusts 25 to 30 kt late morning into the afternoon.

     NY Metro Enhanced Aviation Weather Support...

Detailed information, including hourly TAF wind component forecasts,
can be found at: http:/www.weather.gov/zny/n90

KJFK TAF Comments: Gusts may begin 1-2 hours later than forecast. Wind
direction will stay left of 310 magnetic through this evening.

KLGA TAF Comments: Gusts may begin 1-2 hours later than forecast.
 Wind direction will stay left of 310 magnetic through this
evening.

KEWR TAF Comments: Gusts may begin 1-2 hours later than forecast.
 Wind direction will stay left of 310 magnetic through this
evening.

KTEB TAF Comments: Gusts may begin 1-2 hours later than forecast.


KHPN TAF Comments: Gusts may begin 1-2 hours later than forecast.


KISP TAF Comments: Gusts may begin 1-2 hours later than forecast.

.OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY...
.Friday afternoon...Flurries or snow showers possible NW of the
city. NW gusts 20-30 kt.
.Saturday...VFR.
.Sunday...Mainly VFR with a chance of light snow late.
.Sunday night and Monday...MVFR or IFR in snow Sunday night
changing to mixed precipitation near the coast on Monday.
.Tuesday...Mainly VFR.

&&

.MARINE...
Sub-SCA conditions are expected on the area waters this morning.
This afternoon...the pressure gradient tightens and remains tight
over all the waters through Friday. As a result expect gusts to
25-30 kt over the area waters. The gusts should start a few hours
earlier on the ocean waters than the non-ocean waters, however for
simplicity, have started the SCA everywhere at 18Z today.
Gusts to 35 kt are possible on the ocean tonight and possibly
Friday, however will hold off on any gale warning, thinking that
these gusts would be more occasional than frequent.

Gusty W-NW flow Friday night will diminish as the center of high
pressure builds. Sub SCA conditions are anticipated through the
weekend as the high settles to the south and a frontal boundary
approaches from the west. Low pressure and the associated front
approach and impact the waters Monday. SCA conditions are possible
Monday, particularly across the ocean waters.

Wave/sea forecasts are based on latest NWPS, with WaveWatch
followed toward the end of the forecast. Seas subside as the
winds diminish Friday night and through the weekend.

&&

.HYDROLOGY...
A widespread 1/2 inch or more of liquid equivalent precipitation
is possible from Sunday night through Monday.

&&

.EQUIPMENT...
The New York City NOAA Weather Radio (NWR) transmitter, KWO35, is
off the air. Time for a return to service is unknown.

Central Park (NYC) observations (METAR) are currently
unavailable. Technicians are troubleshooting.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 6 AM EST Saturday for ANZ330-335-
     338-340-345-350-353-355.

&&

$$
SYNOPSIS...BC/PW
NEAR TERM...
SHORT TERM...BC
LONG TERM...PW
AVIATION...CB/JMC/DS
MARINE...BC/Goodman/PW
HYDROLOGY...BC/PW
EQUIPMENT...



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.